The invention relates to a device for inserting and removing a bone nail, along a guide rod that is connected with the bone nail or with an instrument that is connected with the bone nail.
The use of bone nails to aid in the healing of fractures is known. European patent EP 0 528 128 B1 shows a locking nail to correct femur fractures in the middle and trochanter region. In order to drive the nail in or remove it, the locking nail is screwed into an aiming or setting device at its end. For orientation for the operator, the aiming device has a guide rod that points in the longitudinal direction of the nail to be set in.
During the setting process of the locking nail, a medium pressure is exerted on the setting device, driving the nail into the bone. Small rotational movements of the locking nail facilitate its replacement. As a rule, driving the nail in with a hammer should be avoided, since the risk of damaging the bone to be treated is too great. Sometimes, however, it is necessary to drive the nail in with light taps. For this, it is known to use a slit or slotted hammer. The hammer, which is guided along the guide rod with the slit, ensures that the force applied with the hammer taps runs in the longitudinal direction of the nail. When the locking nail is supposed to be removed from the bone, for example, the guide rod is provided with a stop at the end pointing away from the bone. The slit hammer is arranged on the guide rod and the locking nail is removed by tapping the hammer against the end of the guide rod.
The invention is based on the task of making available a device for driving in and removing a bone nail along a guide rod, which device has a structure such that guidance of the tool is made reliably possible, while providing ease of handling.
The device according to the invention, for driving in and removing a bone nail of the type indicated above, is secured to prevent lateral removal from the guide rod. Lateral access to an axial channel makes it possible to set the head element against the guide rod, and to secure it there to prevent it from accidentally slipping off, or to prevent missing the bone nail with the hammer. Such a secured guide is particularly advantageous when removing the nail. The cylindrical or barrel-shaped structure of the head element gives the operator a clear view of the locking nail, i.e. its aiming device, when using the device according to the invention. It is preferred that the cylindrical head element is provided with tapping surfaces at its faces.
In the preferred embodiment of the invention, the lateral access possesses three segments connected with it, where a central segment stands perpendicular to the channel and two end segments that each follow the central segment run in an axial direction along the channel, in each instance, where the end segments are aligned in such a way that the head element set onto the guide rod with the central segment is put into a secured, locked position by means of a rotation during which the end segments take up the guide rod. Preferably, the central segment is at 90xc2x0 perpendicular to the guide direction, so that a 90xc2x0 rotation of the head element is necessary in order to achieve the locked position. The head element can be provided with a handle element that preferably points in the radial direction of the head element.